Electric furnace



(No Model.)

B. H. & A. H. OOWLES.

ELECTRIC FURNACE.

No. 360,144. Patented M21129, 1887.

1,0120% ass/2S:

UNITED STATES PATENT OFFICE.

EUGENE H. 'COXVLES AND ALFRED H. COVLES, OF CLEVELAND, OHIO.

ELECTRIC FURNACE.

SPECIFICATION forming part of Letters Patent No. 360,144, dated March29, 1887.

Application filed October 16, 1855. Serial No.180,035. (No model.)

To all whom; it may concern.-

Be it known that we, EUGENE H. OowLEs and ALFRED H. COWLEs, citizens o fthe United States, residing at Cleveland, in the county of Guyahoga andState of Ohio, have invented certain new and useful Improvements inElectric Furnaces; and we do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being bad to the accompanying drawings, and to lettersor figures of reference marked thereon, which form a part of thisspecification.

This invention relates to furnaces in which the reduction of ores andchemical compounds, the production of alloys, the refining of metals,and like metallurgical operations are carried 011 by means ofelectricity.

This invention consists in the means by which the varying electricalresistance of the charge in the furnace is made the primary agency inactuating and controlling the feeding of the material to be smelted orreduced.

This invent-ion also consists in the means for automatically regulatingand controlling the charging, feeding, and discharging of a furnace ofthe type hereinafter described through the agency of the electricalresistance of the charge in the said furnace.

This invention further consists in the construction of the furnace, andin the combination therewith of the feeding, discharging, and resistanceregulating apparatus, as hereinafter fully described and claimed,whereby the va rying electrical resistance of the charge in the furnaceis made the primary agency in actuating and controlling the feeding ofthe material to be smelted and discharging the products.

Figure l in the drawings shows a furnace embodying our invention invertical section through the center, with the automatic feedregulatingapparatus attached thereto. Fig. 2 is a modification of the mechanismfor regulating the downward feed of the charge. Fig. 3 is a side view ofthe automatic feed mechanism.

' By means of our invention a desirable regularity and uniformity offeeding or charging the furnace is effectually accomplished, and this isimportant for many reasons, prominent among which may be mentioned thatthe fluctuations of the current are governed and controlled withindefinite limits, the draft upon the motive power is made more constantand uniform, and'the dynamo is relieved from the risks attendant uponsudden or undue variations in the resistance of the external or work ingcircuit.

We will now proceed to more particularly describe our invention withreference to the accompanying drawings, in which similar letters ofreference indicate corresponding parts in allthe figures.

A is the positive electrode, preferably made of electric-light carbon inthe form of a pipe or hollow cylinder.

B is the feed-hopper, preferably made conical in form, and having itslower end attached to the top of the positive electrode.

(1 is the negative electrode, also made of electric-light carbon in theform of a hollow cylinder and fastened to the plate D, which is builtinto the lower portion of the furnace, and to which plate the negativewire of the circuit is connected.

E are the furnace-walls, formed of fire-brick, silica, lime, or otherrefractory material.

F is a lining or filling of fine charcoal, pnr verized lime, and carbon,or other suitable ma terial. This lining surrounds the negativeelectrode 0 and insulates it, and being a bad conductor of heat, as wellas of electricity, it prevents the destruction of the lower part of thewalls and the bottom of the furnace when the furnace is in operation.

G is also a lining of charcoal, lime, and carbon, or other suitablematerial. This lining surrounds the zone of fusion between the positiveand negative electrodes, and extends upward around the said positiveelectrode. This lining G is similar in function and character to thelining F, but is made of coarser material to provide for the escape ofthe gases given off from the charge at the zone of fusion when heated bythe current. Thelining of materiahwhich is a bad conductor of heat andelectricity and which surrounds the zone of fusion, prevents theatmosphere from having access to the charge at this point and combiningwith and destroying the combustible constituents of the charge, instead.of allowing them to remain in contact, when rendered incandescent bytheir resistance to the electric current, with the material to bereduced.

T is an escape-pipe, through which the aforesaid fumes and gases passfrom the upper part of the furnace into the condenser t.

H is a plate covering the top of the furnace, and having a hole, 71, inthe top of it, through which the positive electrode can slide freely.

I isa lever pivoted in the bracket i, attached to the plate H.

J is a screw passing through. a screwthreaded hole in the opposite endof lever I and bearing upon the plate H. The lever I is attached tothefeed-hopper B, and by means of the screw J the said hopper, togetherwith the positive electrode A, attached to it, may be raised or loweredto increase or decrease the width of the zone of fusion, as required, orto compensate for the wear of the electrode.

K is a poker or plunger of carbon placed within the hopper B, andextending downward through the electrode A nearly as far as the zone offusion. This poker is provided with projections for better acting uponthe charge, and is attached at its upper end to the crank 6 of thedriving-shaft L by means of the connecting-rod 7c. The d riving-shaft Lis sup ported in any suitable bearings, l, and is providedwith agear-wheel, Z which engages with a similar gear-wheel, m, of a motor.

As herein shown, the motor consists of a weight, in, hung by the cordat", carried by the drum m the latter being secured to the shaft M, andtransmits the power to the gearl' through the gear m. A brake-wheel, m,is

- carried by the motor-shaft, and a crank-handle, m is provided forwinding up the weight when the cord is run down.

Instead of a weight and cord, a coiled spring or any other equivalentmechanism may be used to operate the feed mechanism.

N is a brake-lever pivoted at one end in the support a, and supported atthe other end, a, by means of the spring 0 and screw 0, which screwpasses through ascrew-threaded hole in any suitable fixed support, 0. Bymeans of the screw 0 the tension of the spring 0 can be regulated. Thebrake-lever N is provided with a projection, a", which engages with theserrations of the brake-wheel m when the brake-lever is in its raisedposition and locks the motor.

P is the elcctro-magnet placed beneath the outer end of the brake-lever.

R and S are the circuit-wires attached, respectively, to the positiveand negative electrodes and the magnet P placed within the circuit.

The essential feature of this furnace is that the resistance isregulated and preserved constant by the movement of the charge itself,and not by the movement of the electrodes as at present practiced. Theaction of the furnace is rendered continuous for a long period, and thetime lost in charging and emptying the furnace as hitherto constructedis saved. The electrodes act as conductors only for conveying thecurrent to the charge, and the heat is generated in the charge itself byits electri cal resistance, the carbon constituents of the chargebecoming incandescent.

The practical operation of the furnace is as follows: The feed-hopper isfilled with the material to be reduced, and the current is passedthrough the wires. This causes an intense heat at the zone of fusionbetween the electrodes, the material is there reduced, and falls throughthe lower electrode into the lower part of the furnace. Theelectro-magnct l is made of just such a power that when the re sistanceat the zone of fusion becomes less and more than the normal amount ofcurrent flows through the said magnet the end a of the brake-lever willbe drawn down against the tension of the spring which supports it. Thismovement of the brake-lever sets free the brake-whecl, and themotor-shaft is free to turn and by means of the driving shalt and crankto operate the poker in the furnace.

The movement of. the poker up and down forces more of the charge in thehopper to de scend into the zone of fusion, and when the resistance isthereby increased to the normal amount the current, which isproportionately decreased, 'allows the eleetro-magnct to let go thebrake-lever, which then stops the movement of the poker. This operationis again repeated upon fresh portions of he charge of material to bereduced, which may consist of ore and carbon mixed together, or otherequivalent resistance material, being fed downward from the hopper andthe reduced metal withdrawn from the bottom.

it will be seen that with this form of furnace the charcoal or carbonimmediately surrounding the zone of fusion renews itself as fast as itbecomes graphitized. It then falls down. into the lower part of thefurnace, or it may be knocked down by moving the upper electrode, as itis desirable to get rid of it as soon as it becomes a good conductor ofelectricity.

lVe do not limit or confine our invention to any specific form orconstruction of mechanism to be employed, inasmuch as any mechanicaldevices may be used which can be actuated and controlled primarily bythe electrical resistance of the charge in the furnace, and which willoperate through such agency to control and govern the feeding of saidfurnace.

We are aware that an electric lamp has been patented abroad in which itwas proposed to obtain light from a stream of pulverized ma terial,caused to flow from a reservoir through one pole of an electric circuit,and thence to the other pole, in contact with the atmosphere, and thatit was proposed to regulate the exitvalve of the reservoir by means ofan electro-' magnet placed in the circuit.

lVe do not broadly claim the system of automatically regulating-thesupply of resistance material between the poles of an electric circuitby means of an electromagnetic device inserted in the circuit.

We are also aware that an electric furnace has been constructed in whichthe length of the are and the distance between the electrodes isautomatically regulated by the resistance of the arc.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent, is

1. In an electric furnace, the combination of two stationary electrodesof opposite polarity, a body of material which is a bad conductor ofheat and electricity surrounding the zone of fusion, a feed-hopper forthe charge to be reduced, and means for automatically moving the chargebetween the said electrodes when the normal resistance is diminished,substantiall y as and for the purpose set forth.

2. In an electricfurnace, the combination of two stationary electrodesof opposite polarity, a body of material which is a bad condoctor ofheat and electricity surrounding the zone of fusion, a feed-hopper forthe chargeto be reduced, a device for moving the charge between the saidelectrodes, mechanism for actuating the said charge-moving device, andan electro-magnet placed -in the circuit and ada 'lted to start the saidactuating mechanism when the normal amount of the current is increased,snbstantially as and for the purpose set forth.

3. In an electric furnace, a hollow cylindrical electrode, a feed-hopperattached to one end of the said electrode, a lever pivoted to thestationary top portion of the furnace for supporting the saidfeed-hopper and electrode, and a screw for regulating the position ofthe lever and causing the said electrode to project more or lesswithinthe furnace, substantially as and for the purpose set forth.

4. In an electric furnace, the combination of two vertical electrodes ofopposite polarity, alining of fine charcoal surrounding the lowerelectrode, a lining of coarse charcoal surrou nding the zone of fusionbetween the electrodes and extending upward around the upper electrode,and the furnace-walls for retaining the said charcoal linings inposition, substantially .as and for the purpose set forth.

In an electric furnace, the combination of the electrodes A and C, thefeed-hopper at tached to electrode A, the poker working back and forthwithin the said hopper and electrode, the driving-shaft provided with acrank for actuating the said poker and with the gearwheel 1*, themotorshaft M, provided with the means for rotating it, the gear-wheel m,and a brake-wheel, the brake-lever having the projection or", engagingwith the brake-wheel, the spring 0, attached to the said brake-lever atits free end, and the electro-magnet P, for disengagingthe brake leverwhen the normal amount of current passing through the mag netisincreased, substantially as and for the purpose set forth.

6. In an electric furnace, the combination of the retaining-walls, theelectrode 0, the fine charcoal lining F, the electrode A, the feedhopperB, the lining of coarse charcoal G, the condenser t, the lever I,pivoted at the top of the furnace for supporting the said feed-hopperand electrode A, and the screw J, for adjusting the position of theelectrode A within the furnace, substantially as and for the purpose setforth.

7. An electric furnace provided with a body of material which is a badconductor of heat and electricity surrounding the zone of fusion, andwherein the electrical resistance of the charge while in the zone offusion constitutes the primary agency whereby the feeding mechanism ofthe said furnace is actuated and controlled, substantially as and forthe purpose set forth.

8. An electric furnace provided with a body of material which is a badconductor of heat and electricity surrounding the zone of fusion, andwherein the charge forms part of an electric circuit and is in contactwith the terminals of the electric circuit, and wherein the varyingelectrical resistance of the said charge due to its temperature andcondition is the agency whereby the action of said furnace feeding orcharging mechanism is actuated and controlled, substantially as and forthe purpose set forth.

9. In an electric furnace wherein the charge fills the space between theelectrodes and is in contact therewith, the combination, with suitablecharging or feeding apparatus, of a body of material which is a badconductor of heat and electricity surrounding the zone of fusion,- andan electromagnetic device actuated and controlled by a current dependentfor its strength and variations upon the varying electrical resistanceof the charge in said zone of fusion, substantially as and for thepurpose specified.

10. In an electric furnace provided with a body of material which is abad conductor of heat and electricity surrounding the zone of fusion,and wherein the charge fills the space between the electrodes and is incontact therewith, an electric circuit which includes the charge insaidfurnace, and-also includes suit able feeding or charging apparatus ormechanism for controlling the same, whereby the electrical resistance ofthe charge shall influence and govern the feeding or charging of saidfurnace, substantially as and for the purpose specified.

In testimony whereof we afiix our signatures in presence of twowitnesses.

EUGENE H. OOWLES. ALFRED H. COWLES. Witnesses:

ROMAINE 0. Corn, E. H. PERDUE.

